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'nitcd Startet @aient @Mira JOSEPH W. HOPKINS, OF BROOKLYN, NEW YORK,ASSIGNOR IO HIMSELF AND WILLIAM.H. M. PYE, OF SAME PLACE.

Leners Patent No. 99,193, dated January 25, 1870.

IMPROVEMENT IN AIR-PUMPS.

The Schedule referred to in these Letters Patent and making part of thesame.

To all whom 'it muy concern Be itknown that I, JOSEPH W. HOPKINS, ofBrooklyn, in the county of Kings, and State of `New York, have inventedandA made a new and useful Improvement in Pumps for Air, 85e.; and I dohereby declare the following to be a full, clear, and exact descriptionofthe said invention, reference being had'to the annexed drawing, makingpartof this specification, where-- 1n- CP1`igure l is a longitudinalsection of the said pump, an

Figure 2 is a transverse section ofthe same, at the line x x..

Similar marks of reference denote same part-s.

Heretofore, in the manufacture of air-pumps, especially large ones, forvacuum-pans in sugar-refineries, there has been great troubleexperienced in keeping the pump i-u order, and obtaining a good vacuum,because the valves become defective, and there isno opportunity forremoving obstructions with facility, and

repairing any defects.

Another fruitful source of diiculty arises from the expansion orcontraction of the metal, rendering the valve-seat out of true with thevalve. This latter difoulty arises from the valve-seat usually being thesurface of a portion of the cast-metal cylinder, or of the valve-chest.

My invention is designed to facilitate the construe; tion of the valves,and grinding them to their seats, and to prevent the valve or seatbecoming defective in operation, in consequence of expansion or contrac-`tiren.

- 'To effect these objects, I employ separate detachable valve-seats,fitted so that they can be mounted with the valves, and prepared for usewhile separate from the cylinder, and then, when completed, thevalve-seat can be slipped into place, and the parts ap# plied thereto.This enables n'ie to make the valves and seats with the greatest careand accuracy, and

defects in the metal forming the valve-seats, or in the workmanship, areavoided.

In the drawingais the cylinder, forming, with the piston b, and heads cc, a pump forair, water, or other uids, and

- these parts are to be of any usual or desired size or proportions.

d is the induction-pipe, leading into the spaces e e, below the valves fj, that are above the seat-plates i, and within the spaces 7c, leadingto the induction-ports l.

an m are the eduction-ports, that diverge, as seen in iig. 2, to come upbeneath the respective valves f'; and u are the valve-covers, and o, theeduction-pipes and passages.

The valves ff are all formed as disks upon spindles 2, and small spiralsprings are employed to press the valves down to their' seats. p

These valves are formed in ranges or groups, and the seat-plate z' ofeach group carries, by pillars 4, the stem-bar r, through which thevalve-stems pass.

The seat-plates i are formed 'with dovetailed edges, and the recessesreceiving them are similarly shaped, so that after each group of valveshas been properly constructed, and the valves ground and tted each toits seat, the seat-plate can be slipped into its place, and then the capput upon the pump.

This construction allows for removing any group of valves with greatfacility, for` freeing any valve from an obstruction, or regrinding thevalve to its seat.

By winding the spring for each valve in a conical form, considerablelplay can be given to the valve, wit-hout the possibility of the springbeing injured.

If desired, each valve may-have a face of India rubber, to preventv thenecessityv of grinding the valve to the seat.

This pump, when employed for maintaining a Vacuum in sugar or otherapparatus, may have a small quantit-ybf water in it, to iill theotherwise unoccupied spaces and passages at the end of each stroke.

That I claim, and desire to secure by Letters Patent, is

The movable seat-plates i and stem-bar 1', in combination with thedisk-valves and the cylinder and piston of' a pump, substantially as andfor the purposes set forth.

In witness whereof, I have hereunto set my signature, this 29th day o i'J une, 1869.

JOSEPH W. HOPKINS.

'itnesses GaAs. H. SMITH, GEO. T. PINCKNEY.

